Japanese pumice or Hyuga as it is known in Japan is a naturally occurring volcanic product from the south part of Miyazaki Prefecture in Japan.
Hyuga is a high porosity bio-media that provides efficient biofiltration for the removal of nitrogenous waste. Plastic bio-materials provide only external surface area, whereas Hyuga provides both external and internal macroporous surface area. These macropores are ideally sized for the support of nitrifying and denitrifying bacteria. This allows Hyuga, unlike other forms of media, to remove nitrate along with ammonia and nitrite, simultaneously and in the same filter.
Hyuga is completely inert and will not breakdown. It need not be replaced. Since the majority of the bacteria are internal, Hyuga may be rinsed when needed without damaging the filter. Hyuga is compatible with all types of wet or wet-dry filters.
Use 250 mL of Hyuga for each 200 L (50 US gallons)** of water. Hyuga may be placed in any kind of filter and is particularly effective in a canister filter. Hyuga works well in drip tray systems, but you may find that the larger Hyuga Medium/Small is better suited for such applications.